1. Field of the Invention
The present invention relates to a method of film-coating medicines, and particularly it relates to a method of film-coating which comprises putting a prescribed dose of a medicine between two sheets capable of releasing said medicine wrapped therein within the intestines or securing it in a receptacle formed of said film as the film-forming substance, and then putting the two films together by fusion or adhesion.
2. Description of the Prior Art
The film-coating method has hitherto been widely used because it has such advantages that, because a high-molecular film-forming substance is used, the resulting film is stable, and, because of the adoption of the hand-coating process or the spray process in applying an organic solvent solution of said substance, the operation is simple.
However, the conventional film-coating method has been defective in that, (1) inasmuch as it employs a process comprising dissolving said film-forming substance in an organic solvent or water and forming a coating film with the resulting solution, the object-to-be-coated must have a shape like a tablet and, accordingly, it has been impossible to apply a film-coating directly to a pulverized or a liquid medicine; (2) in the case of employing the spray process, since the bore of the nozzle for spraying is limited and the viscosity of the film-forming solution is restricted, in order to facilitate the spraying, it is required to lower the viscosity of the film-forming solution and it is inevitable to reduce the molecular weight thereof, causing deterioration of the strength of the resulting film and the occurrence of cracks therein, and moreover, inasmuch as the coating layer consists of spray particles, it is fragile and apt to exfoliate; (3) when an organic solvent is employed in the coating process, there is a fear of causing various troubles such as explosion or fire, public nuisance owing to the exhaust gas as well as the waste water, the question of employee health related to inhalation by working personnel, etc.; and (4) since the stamping or printing of minute letters or marks on every tablet is usually performed after finishing the coating, it has been difficult to ensure a definite, fine indication on the spherical surface of the resulting tablet.